This invention relates to end blocks adapted to be disposed along the leading and trailing edges of a kiln car. These blocks are sometimes referred to as end seal blocks. Ceramic and/or refractory goods are usually loaded onto kiln cars and transported by the cars through a kiln to be dried or fired. The kilns are generally heated from the top or side and some type of insulating barrier is usually maintained to protect the understructure of the kiln cars. At high temperatures, and especially after repeated runs through a kiln, the heat may cause the wheels, axles, bearings and other portions of the truck and frame assemblies of the cars to deteriorate, warp or otherwise become defective. Additionally, the goods which are transported through the kiln should be dried or fired in the presence of uniform heat throughout the kiln. If cool drafts from the lower regions of the kiln are allowed to reach the goods, they may be adversely affected, such as by incomplete firing or drying, slumping, cracking, etc.
For these reasons, various refractory materials are usually placed on or associated with the kiln car to prevent the transfer of heat from the top of the kiln to the area beneath the load bearing surface of the kiln car and to prevent the transfer of cold air from beneath the kiln car to the area above its load bearing surface. Various shapes of side blocks have been used to prevent heat or cool air from going down or up the sides of the kiln to the area below or above the load bearing surface of the kiln car. These side blocks are generally disposed very close to the walls of the kiln or in overlapping relation with portions of the kiln walls to prevent the heat from reaching the underframe of the car and to prevent the cool air from reaching the goods on the car. End seal blocks have been used on the leading and trailing ends of kiln cars to provide a heat seal between adjacent cars. Examples of various arrangements to prevent the transfer of heat from a kiln to the area below the load bearing level of kiln cars are disclosed, for example, in U.S. Pat. No. 379,040 of Anderson, issued Mar. 6, 1888; U.S. Pat. No. 1,072,302 of Boss, issued Sept. 2, 1913; and U.S. Pat. No. 3,363,324 of Martin, issued Jan. 16, 1968.
Conventional end blocks have portions adapted to overlap or abut mating or similar portions of end seal blocks on an adjacent kiln car. If the mating or abutting portions are too close to the corresponding portions of the end seal blocks of an adjacent car, they will tend to become damaged due to contact with one another. If the mating or abutting portions do not come into contact with each other, as in the case in the prior art, there may be unwanted and detrimental heat transfer below and above the level of the load bearing surface of the kiln cars. Furthermore, pressurization of the furnace atmosphere can sometimes overcome the tortuous path.
Various types of interlocking building blocks are known. See, for example, those disclosed in the following U.S. patents: U.S. Pat. No. 868,838 of Brewington, issued Oct. 22, 1907; U.S. Pat. No. 1,088,040 of Stanton, issued Feb. 24, 1914; U.S. Pat. No. 1,162,409 of Shimer, issued Nov. 30, 1915; and U.S. Pat. No. 4,003,172 of Pawl, issued Jan. 18, 1977. Moreover, refractory bricks are known wherein portions of the brick interlock with portions of another brick. See, for example, U.S. Pat. No. 1,330,249 of Emley, issued Feb. 10, 1920; U.S. Pat. No. 1,410,729 of Balz, issued Mar. 28, 1922; U.S. Pat. No. 1,925,103 of Loftus et al., issued Sept. 5, 1933 and U.S. Pat. No. 2,075,863 of Nash, issued Apr. 6, 1937. U.S. Pat. No. 3,077,703 of Bergstrom, issued Feb. 19, 1963, discloses a roof deck structure having a tongue and groove structure with moisture barrier means associated therewith.
None of these patents disclose an end seal block having the structure or improved function of the end seal block according to the present invention.